The Jewish idea is that the Torah of Moses is a truth for all humanity, whether Jewish or not. The Torah (as explained in the Talmud - Sanhedrin 58b) presents seven mitzvot for non-Jews to observe. These seven laws are the pillars of human civilization, and are named the “Seven Laws of Noah,” since all humans are descended from Noah. They are:

  1. Do not murder.
  2. Do not steal.
  3. Do not worship false gods.
  4. Do not be sexually immoral.
  5. Do not eat a limb removed from a live animal.
  6. Do not curse God.
  7. Set up courts and bring offenders to justice.

Maimonides explains that any human being who faithfully observes these laws earns a proper place in heaven. So you see, the Torah is for all humanity, no conversion necessary.